Due to the chaotic nature of 4chan, there will never be a canon for the board-tans. There may be consensus, but it is best to treat all of the characters as fanon. If a certain character design upsets you, use the interpretation that you like the most, or be a real fa/tg/uy and make your own.

Once upon a time, an image was posted on the /r9k/ board of 4chan labeled "4chan house" that showed all the then-boards of 4chan as little stick figures doing board-relevant things. Then a drawfag named Three Angled Blue drew a comic immortalizing /b/'s failed invasion of /v/, showing both boards personified as characters. A new era dawned unexpectedly.

Prior to these events, 4chan's boards did not have character representations. There was always the portrayal of Anonymous as the featureless green-skinned "[No Picture Available]" man-in-a-suit, and there were certainly mascots, but a character that was a whole board? Preposterous.

Fast forward some years through multiple iterations of failed group projects, thread deletions, and moderate obscurity and you get to where we are today: a vast and rather unorganized collection of scribbles, fiction, and even cosplays that portray the various boards of 4chan as anthropomorphized characters living out their crazy lives.

Some thought it brilliant, and others equated those people to fanfiction-loving scum. In the end, it's a matter of taste.

The -tan suffix is a weeaboo holdout, in the vein of the OS-tan characters.